/Engine/Source/Runtime/GeometryCore/Public/Spatial/BlockedDenseGrid3.h
Methods on the block's default values.  The block 'default value' is returned when querying a cell in an unallocated block, and is used to initialize the block on allocation.
the default value for the specified block.
ElemType GetBlockDefaultValue ( const [FVector3i](API\Runtime\GeometryCore\FVector3i) & BlockIJK ) const